Add three Chinese locale variants with region-specific flags:
- zh-TW: Traditional Chinese (Taiwan) 🇹🇼
- zh-HK: Traditional Chinese (Hong Kong) 🇭🇰
- zh-CN: Simplified Chinese (China) 🇨🇳
Each variant uses region-appropriate terminology (e.g. 郵件/電郵/邮件
for "email"), consistent with the existing pattern of tying languages
to specific regions (e.g. Spanish (Spain), Portuguese with 🇧🇷).
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
